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HORATIO ALLEN, OF NEW YORK, N. Y.

CUT-OFF VALVE FOR STEAM-ENGINES.

Specification of Letters Patent No. 2,597, dated April 80, 1842.

To all 'wlw/m, t may concern Be it known that I, Horario ALLEN, of the city and county ot New York, in the State of New York, have made certain Improvements on my Invention for which Letters Patent for Improvement in the Cut- Off Valve for Steam-Engines were granted me August 2l, 1841, and that the following is a full and exact description otsaid additional improvements.

In the original specifications I described, by reference to Plates 3 and 4 Figures 5, G, 7 and 8 the arrangement therein denominated cut oil with adjustable seats wherein a cut off slide or two cut oit slides on the same rod, are combined with two adjustable seats, one for each end of the cylinder, and each containing an opening for the passage of steam to its respective end.

As a further improvement, I propose t-he combination represented in Plates I and II, a reference to which will render the description more concise and clear.

S is t-he steam chamber, in which are placed the cut od slides C and C.

O is the opening leading to one inner steam chamber, and C the opening leading to the other; both being' in one plate P. Then the slides C, and C cover the openings, the passage of the steamV is cut oil". The slides C and C are by the rods r and r connected with opposite ends of the beam B, which receives a vibratory motion from the rock shaft R, which receives its motion, either from the cross head of piston rod, in the manner represented in the drawing, or other similar methods o-r from an eccentric or cam on the engine shaft.

As the parts are represented in the drawings, and supposed in motion in the directions indicated by the arrows, the steam is cut oli by the slide C, at half stroke, and on the return stroke, it is evident that the other slide C', will cut ott the steam also at half stroke. I propose to make this arrangement adjustable, either by making the plate P movable, which is the plan represented in Plate I, and which I denominate cut oli' with single adjustableseat, or by making the rock shaft R movable, which is the plan represented in Plate I, and which I denomif nate cut off with movable rock shaft?? In the first case (see Plate I) the plate P, which contains both openings O and O, is by the rod t connected with the lever L. It is evident that if the lever L be raised' or depressed, the openings O and O will be raised or depressed, and the proportion of cut off will be increased or diminished, and that the openings can be so placed that no steam will be cut off, or in another position, so that no steam will be allowed to pass.

In the second case (see Plate II) the rock shaft R is supported by the lever L, and the plate P is stationary. It is evident that when the leverL is raised the rock shaft R will be raised, and consequently both the slides C and C will be equally raised, and thus the steam will be cut off at an earlier point in the stroke, and if depressed will be cut oft at a later' point in the stroke. It' the width a, b of the slide, be as much greater than the extent of its' movement, as the width of the opening, then the slides can be placed in a position that will allow no steam to pass during any part of the movement, and if the slides be so depressed, that they do not cover the openings except at the end of the stroke, then the engine will work at full stroke. The rock shaft may in various other ways have a movable support, as by being attached to parts through which a screw runs, in which case, when the screw is turned the parts carrying the rock shaft will be either raised or depressed. The principle of the combination is essentially the same viz that of raising or depressing the rock shaft while the beam, slides &c. may be in full motion. i

The combination represented in Plate II is not limited to the use of the slide valve. but can be used with any valve 'that is at liberty to pass over or through the opening which it closes, either by covering it as is the case with the slide valve, or by entering it, as would be the case when a plunger enters the mouth of a cylinder or pipe which it closely tits. Such a combination is represented in Fig. Plate I. The pipe T leads to one end of t-he cylinder, the pipe B to the other end. The plungers P and P enter the openings O and O', and fit them as nearly as practicable. As the parts are represented, and being supposed in motion in the direction indicated by arrows, the plunger P enters the opening O, and cuts oil:l the steam at half stroke. It the rock shaft be raised or depressed by the lever L, the .proportions of cut ott' will be changed in like manner.

y To embrace the improvements herein described, I make the following claims:

l. The combination oftwo slide valves,

rand said supports of rock shaft being such that they can readily be raised or depressed at pleasure, in the directions of the alternating motions of the valves, without interrupting their movements.

I testimony whereof I the said HoRATIo ALLEN hereto subscribe my name in the presence of the witnesses whose names are hereto subscribed on the twentieth day of April,

HORATIO ALLEN. Witnesses:

JNO. S. WooDwARD, WM. J. SINCLAIR. 

